The BC Liberals could stand to lose seats in two former strongholds as voters in Port Moody-Coquitlam and Chilliwack-Hope head to the polls in byelections Thursday.

NDP candidate and former Port Moody mayor Joe Trasolini appears to be the frontrunner in the first vote, but Chilliwack-Hope is considered a tighter race with very high stakes.

"In many ways, perhaps highest expectations are on the BC Conservatives. If they win this, in a way it confirms the momentum they've had and it will continue to build their support through the rest of the year. If the NDP win, it will be interpreted as, has the right been split and will this mean a massive NDP majority in the next May 2013 election," University of Victoria policy professor Michael Prince told CTV News.

The campaign has taken a nasty turn in Chilliwack, where the Conservatives have lost so many election signs to vandals the party has started mapping out the locations.

"We've been vandalized probably about 10 times what you would expect during an election like this," Conservative candidate John Martin said.

His upstart party believes it has a real chance of winning the seat on Thursday.

"We're challenging parties that are much more organized, have a much bigger bankroll than we do, and we've got them on the run," Martin said.

NDP candidate Gwen O'Mahony, who was joined by former party leader Carole James on the campaign trail Wednesday, said she's expecting a close race as well.

"I think it's a tight three-way right now. That's the feeling I get," she said.

But Liberal Laurie Throness doesn't believe the Conservatives have a real chance of victory.

"I think the Conservatives can spoil it, they can divide the vote, but they will not be able to win. That's according to the numbers that we have," he said.

His party leader, Premier Christy Clark, turned her attention to the Port Moody-Coquitlam race Wednesday, with pointed criticism of Trasolini, a former Liberal.

"Joe used to be someone who supported free enterprise, and he did for years, and then he was talking to two parties at the same time about running for both of them, and I don't think that demonstrates a lot of character," Clark told reporters.

Trasolini was a friend of Clark's and supported her bid to lead the Liberals. He said he intends to "take the high road" in the face of the premier's remarks and run with a positive message in the waning hours of his campaign.

"My core values are the same, very similar to the NDP core values. I'm the same individual with the same politics, still balanced, and I made a choice," Trasolini said.

His Liberal competition, Dennis Marsden, said he's been getting a good response from voters despite not having the name recognition of the former mayor.

"It can be seen as a positive, it can be seen as a negative, when you've been around and in politics as long as Mr. Trasolini has been. You make some friends and you find a lot of people that aren't quite as positive," Marsden said.

The contested riding was once held by the current premier, and the Conservatives candidate is the similarly-named Christine Clarke.

But Clarke says that her name isn't an advantage.

"If there is name confusion, I think it will do me more harm than good, but I think most people will figure it out," she said.

With reports from CTV British Columbia's Michele Brunoro and Ed Watson